Correlation Between Resilient Modulus and Permanent Deformation During a Large Scale Model Experiment of Unbound Base Course

2017 ◽  
pp. 377-384 ◽  
Author(s):  
Makhaly Ba
Keyword(s):  
Model Experiment ◽  
Large Scale ◽  
Resilient Modulus ◽  
Permanent Deformation ◽  
Scale Model ◽  
Large Scale Model ◽  
Base Course

scholarly journals Deflection characteristics of Unbound Base Course During a Large Scale Model Experiment

2015 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Makhaly Ba ◽  
Meissa Fall ◽  
Oustasse Abdoulaye Sall
Keyword(s):  
Cyclic Loading ◽  
Model Experiment ◽  
Large Scale ◽  
Scale Effects ◽  
Base Layer ◽  
Scale Model ◽  
Pavement Materials ◽  
Elastic Deflection ◽  
Large Scale Model ◽  
Base Course

This paper evaluates de deflections (measured at the surface and/or at the top of the subgrade) of unbound pavement materials under cyclic loading. Deflections of three base course materials (Bakel Red Quartzite, Bakel Black Quartzite and Diack Basalt) were investigated using a large-scale model experiment (LSME). The LSME is a prototype-scale pavement test apparatus where cyclic loading is applied and deflections are measured. The LSME replicates field conditions and accounts for scale effects. The LSME results showed that the total, plastic and net plastic deflections of a pavement increase progressively as the number of loading cycles increases. The total deflection decreases as the thickness of the base layer increases. Plastics deflections at the top of the subgrade decrease progressively as the thickness of the base layer is increased. The elastic deflections of the surface and of the base layer decrease gradually with the increasing loading cycles. The elastic deflection at the top of the subgrade decreases with increasing thickness of the base layer. So, rutting can be limited by limiting the elastic deflection at the top of the subgrade. However, this criterion does not account for the rutting caused by the unbound base layers and that of the asphalt concrete.

Structural Contribution of Geosynthetic-Reinforced Working Platforms in Flexible Pavement

2005 ◽  
Vol 1936 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Woon-Hyung Kim ◽  
Tuncer B. Edil ◽  
Craig H. Benson ◽  
Burak F. Tanyu
Keyword(s):  
Model Experiment ◽  
Large Scale ◽  
Elastic Moduli ◽  
Granular Layer ◽  
Resilient Modulus ◽  
Scale Model ◽  
Design Guideline ◽  
Large Scale Model ◽  
Structural Contribution ◽  
Soft Subgrade

A study was conducted in the field and with a large-scale model experiment (LSME) to evaluate the structural contribution of a 0.30-m-thick geosynthetic-reinforced granular layer used as a working platform for construction over soft subgrade. The study was conducted in the context of the 1993 AASHTO design guideline, in which the structural number (SN) of the pavement is based on layer coefficients (each defined using a resilient modulus). Working platforms reinforced with geosynthetics had smaller elastic deflections and larger elastic moduli than unreinforced working platforms with the same thickness. Reinforcement factors obtained in the field ranged from 1.2 to 1.8; those obtained in the laboratory ranged from 1.7 to 2.0, with greater reinforcement factors for the less extensible geosynthetics (geogrid, woven geotextile) for a 0.3-m-thick granular working platform. Of the four geosynthetics tested, the geogrid resulted in the greatest increase in modulus. Reinforcing the working platforms with geosynthetics resulted in increases in layer coefficients ranging from 50% to 70%. Similarly, increases in SN for a typical pavement structure were realized, ranging from 3% to 11% when all other factors were equal.

Development of Methodology to Include Structural Contribution of Alternative Working Platforms in Pavement Structure

2005 ◽  
Vol 1936 (1) ◽  
pp. 70-77
Author(s):  
Burak F. Tanyu ◽  
Woon-Hyung Kim ◽  
Tuncer B. Edil ◽  
Craig H. Benson
Keyword(s):  
Large Scale ◽  
Resilient Modulus ◽  
Bottom Ash ◽  
Scale Model ◽  
Design Charts ◽  
Large Scale Model ◽  
Design Guide ◽  
Structural Contribution ◽  
Analysis Design ◽  
Industrial Byproducts

A methodology was developed to incorporate the structural contribution of working platforms, including those constructed with industrial byproducts, into the design of flexible pavements. Structural contribution of the working platform was quantified with the 1993 AASHTO flexible pavement design guide in terms of a structural number or an effective roadbed modulus. Two methods are proposed. One method treats the working platform as a subbase layer and assigns a structural number to the working platform for use in computing the overall structural number of the pavement. The other method adjusts the effective roadbed modulus to account for the improvement in the roadbed provided by the working platform. Resilient modulus obtained from large-scale model experiments conducted on several working platform materials (e.g., breaker run stone, Grade 2 gravel, foundry slag, foundry sand, and bottom ash) was used in the analysis. Design charts show the structural number or the roadbed modulus as a function of type of material and thickness of the working platform.

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